Automatic stripping machine for abaca and allied fiber bearing plants

ABSTRACT

A method and apparatus for defibering sheaths of fibrous material, particularly Manila hemp, by conveying the sheaths past several stationary blades arranged in the path of travel of the sheaths whereby the edges of the blades separate the fibrous parts of the sheaths from the pulpy parts.

nited States Patent Villanueva et al.

[451 June 20, 1972 [54] AUTOMATIC STRIPPING MACHINE FOR ABACA AND ALLIEDFIBER BEARING PLANTS [72] Inventors: Juan T. Villanueva; Jesus T.Vlllanueva,

both of 105 Apo Street, Sta Mesa Heights, Quezon City, Philippines 22Filed: June 4,1969

21 Appl.No.: 830,449

[30] Foreign Application Priority Data June 4, 1968 Philippines ..9282

[52] US. Cl ..l9/l2 [51] Int. Cl. ..D0lb H10 [58] Field otSearch ..l9/5,6,10,11,12, 13, 27, 19/1, 7, 8,15,17,19, 20, 34

[56] References Cited UNITED STATES PATENTS 852,410 5/1907 Barton l 9/341,258,571 3/1918 Humphrys ..19/8 1,390,922 9/1921 O'Neill, Jr. ....l9/l21,725,815 8/1929 Mertz ....l9/l2 2,759,224 8/1956 Simons ..19/1 IFOREIGN PATENTS OR APPLICATIONS 211,113 10/1957 Australia ..l9/27 23,3077/1949 Finland 1 9/12 528,765 1 H1940 Great Britain ..19/13 PrimaryExaminer-Dorsey Newton Attomey-Michael S. Striker ABS I RACT A methodand apparatus for defibering sheaths of fibrous material, particularlyManila hemp, by conveying the sheaths past several stationary bladesarranged in the path of travel of the sheaths whereby the edges of theblades separate the fibrous parts of the sheaths from the pulpy parts.

9 Claims, 29 Drawing Figures AUTOMATIC STRIPPING MACHINE FOR ABACA ANDALLIED FIBER BEARING PLANTS BACKGROUND OF THE INVENTION I This inventionrelates to a method and apparatus for stripping leaf sheaths or tuxiesas they are more commonly known, from the Manila hemp plant, also knownas abaca and scientifically classified as musa textilis, linnaei.

Until the present time there have been only two methods used to extractthe fibers from Manila hemp, namely decortication and stripping.

Manila hemp or abaca, a plant which is indigenous to the Philippines,bears a striking resemblance to the banana plant, both plants beingbotanically classified in the genus musa. The main difference betweenthe two plants however is that the abaca plant is somewhat smaller thanthe banana plant, otherwise the plants a.re similar in many otherrespects, particularly in regard to their structure. The trunk, whichappears to be rounded, is actually made up of crescent-shaped layers,within which the fibers are found on the outer or convex side of thecrescent, and there is a pulpy material on the inside or convex side ofthe crescent, as well as within the body of each layer. Eachcrescent-shaped layer is called a leaf sheath, or more commonly, atuxy". Each tuxy converges in an upward direction from the base of theplant to form a round stalk which becomes a mid-rib from which a leafspreads outon either side of the mid-rib. The trunk of the abaca plantis known as a leaf stalk" before the tuxies which constitute it areseparated from it.

The decortication process involves repeated beating of the tuxies byhand, or in some instances the entire trunk is beaten in order to exposethe fibers. To remove the sap the fibers are simultaneously washed in aconstant supply of water as the beating occurs along the entire lengthof the trunk. The fibers produced by this process have a dull appearancein contrast to the fibers produced by stripping. In addition, both thepulp and sap are carried away by the wash water.

In the stripping process, each leaf sheath is pulled between a strippingelement comprising a blade and a wooden or plastic block which presseson the inserted leaf sheath as it passes over the blade. In this manner,the sap is squeezed out of each tuxie, first from one portion of theleaf stalk and then from the remaining portion. As a result of thisoperation, the entire tuxy is completely defibered without washing insuch a way that only the strongest fibers pass through the strippingelement while the relatively weaker fibers remain behind the strippingelement together with the waste pulp. The shape of the cutting edge,i.e. plain or serrated, greatly determines the commercial grade of thestripped fibers, thus the absence of the weaker fibers makes thestripped fibers stronger and of a better quality than the fibersobtained by decortication.

Presently known machines used for decortication of Manila hemp fibershave been developed to quite an advanced state of the art, whereas thestripping process is for the most part still done by hand. A machine ispresently known which is used to mechanize the stripping process,however it is .dangerous to use and its effective production is largelydependent upon the skill of its operator.

SUMMARY OF THE INVENTION It is an object of this invention to provide anovel method and apparatus for the automatic stripping of fiber-bearingplants, particularly the Manilahemp plant.

Another object of this invention is to provide a novel means for theautomatic and systematic classification of stripped Manila hemp fiber.

Another object of this invention is to provide a novel mechanical meansfor the extraction of Manila hemp fiber from the midribs of the leavesof the plant.

A further object of this invention is to provide a novel mechanicalmeans for the extraction of the finest grades of Manila hemp fiber.

The method of the present invention comprises the steps of positivelyengaging and transporting successive sheaths sideways past at least onestripping station and stripping the pulpy part from the fibrous part ofthe sheaths during travel v past said station.

The stripping step is carried out in a number of successive stages andthe transporting step includes gripping the sheaths and imparting tothem an undulate shape.

The apparatus of the present invention comprises conveyor means forpositively engaging and transporting successive sheaths sideways, andstripping means including a plurality of stationary stripping bladeshaving edges located in the path of travel of the sheaths toautomatically strip the pulpy part from the fibrous parts of thetravelling sheaths.

The novel features which are considered as characteristic of theinvention are set forth in particular in the appended claims. Theimproved stripping machine however, both as to its construction and itsmethod of operation, together with additional features and advantagesthereof, will be best understood from the following description ofspecific embodiments when read in connection with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a plan view of oneembodiment of the automatic veyors, the upper chain belt conveyors, andthe stripping elements;

FIG. 2 is a plan view of an alternative embodiment of the automaticabaca stripping machine showing the lower chain belt conveyors, theupper conveyors, and the stripping elements;

FIG. 3 is a schematic side view of the automatic abaca stripping machineshown in FIGS. 1 and 2 showing the lower chain belt conveyors and thestripping elements, with their respective wedge shaped openings oringresses where the raw material is inserted;

FIG. 4 is a schematic plan view of the upper or top chain belt conveyorsshowing their respective locations over their corresponding lower chainbelt conveyors featured in FIGS. 1 and 2;

FIG. 5 is a schematic side view of all the upper or top chain beltconveyors showing their arrangement in the stripping machine;

FIG. 6 is a schematic side view of the upper chain conveyor 40 whichlies over lower chain belt conveyor 41 shown in the next drawing, i.e.FIG. 7;

FIG. 7 is a schematic side view of the lower chain belt conveyor 41;

FIG. 8 is a schematic side view of upper chain belt conveyor 42 which isplaced over the lower chain belt conveyor 43 shown in the next drawing,i.e. FIG. 9;

FIG. 9 is a schematic side view of lower chain belt conveyor 43;

FIG. 10 is a schematic side view of upper chain belt conveyor 44 whichis mounted over the lower chain belt conveyor 45 shown in the nextdrawing, i.e. FIG. 11;

FIG. 11 is a schematic side view of lower chain belt conveyor 45;

FIG. 12 is a schematic side view of upper chain belt conveyor 46 whichlies over lower chain belt conveyor 47 shown in the next drawing, i.e.FIG. 13;

FIG. 13 is a schematic side view of lower chain belt conveyor 47;

FIG. 14 is a schematic side view of upper chain belt conveyor 48 whichlies over lower chain beltconveyor 49 shown in the next drawing, i.e.FIG. 15;

FIG. 15 is a schematic side view of lower chain belt conveyor 49;

FIG. 16 is a schematic side view of upper chain belt conveyor 50 whichlies over lower chain belt conveyor 51 shown in the next drawing, i.e.FIG. 17;

FIG. 17 is a schematic side view of lower chain belt conveyor 51;

FIG. 18 shows in cross-sectional detail the design and construction of aset of chain belt conveyors provided with ropes between which the leafsheaths are tightly held while being conveyed through the strippingprocess;

FIG. 19 is a plan view of the design and arrangement of the conveyorsshown in FIG. 18;

FIG. 20 is a side elevational view of the design and arrangement of theconveyors shown in FIGS. 18 and 19;

FIG. 21 depicts in cross-sectional detail an alternative conveying meansin the form of a pair of flat rubber belts provided with treadcorrugations containing small reinforcing cords or ropes built into thebelts;

FIG. 22 is a plan view showing in detail an alternative design of theset of conveyors shown in FIG. 21;

FIG. 23 is a side view of the conveyors illustrated in FIGS. 21 and 22;

FIG. 24 shows the initial stripper element 65;

FIG. 25 shows the anterior portion of the initial stripper element 65,i.e. before the bend thereof, and in profile shows the relative positionof the leaf sheath inserted between the rounded edge of the strippingblade and the wooden or plastic stripping block pressing upon itpreparatory to the stripping process;

FIG. 26 shows the posterior portion of initial stripper 65, i.e. afterthe bend thereof, and shows in profile the relative position of the leafsheath and the resulting fibers during the stripping process;

FIG. 27 shows the final stripper element set 74;

FIG. 28 shows the anterior portion of final stripper element set, i.e.before the bend thereof, and shows in profile the relative position ofthe leaf sheath upon insertion between the rounded edge of the strippingblade and the wooden 'or plastic stripping block pressing upon itpreparatory to the stripping process; and

FIG. 29 shows the posterior portion of final stripper element 74, i.e.after the bend thereof, and shows in profile the relative position ofthe leaf sheath and the resulting fiber during the stripping process.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2 ofthe drawings, power is received by the machine from any form of primemover or from an electric motor of sufficiently large power ratingthrough multiple V-belts applied upon a grooved pulley 100 which causesshaft 102 to turn clockwise looking in the direction of the travel ofthe material from the entrance end of the machine to the exit andthereof. The axis of shaft 102 is kept in position by means of journals101. Power is transmitted mechanically from shaft 102 to shafts 103 keptin place by pillow block bearings or journals 97, through the use ofeither bevel gears 98 and 99 or corresponding silent spiral gears.

The sprockets mounted and fixed or keyed to shafts 103 cause the forwardmovement of all the lower chain belt conveyors. Power is transmitted tothe sprockets and to the conveyor driven by them directly through theshafts 103 except in the case of lower chain belt conveyor 43 where adirect drive cannot physically be arranged because of the obstaclepresented by stripper element 74. This simple mechanical problem findsan easy solution in the installation of a countershaft parallel to shaft103 to be placed possibly below it, upon which spur gears will be keyedat the ends, said countershaft to be supported by a couple of journalsappropriate for the purpose so that with a ratio of l to l, motion istransmitted from spur gear 104 to spur gear 105 provided for the drive.This gear 105 is mounted upon shaft 106 running within journals 107. Inthis manner the lower conveyors are caused to move forward. How theycause motion of the upper or top conveyors will be explained in moredetail below.

In this invention, it is proposed to have all top conveyors driven bytheir respective lower conveyors by means of a set of four gears, two ofwhich to be accurately set to be always in mesh with each other whileeach of them are set to be always meshing with the driving and drivengears of the gear trains respectively in a conventional arrangement.

In order to derive the greatest possible advantage from the use of theautomatic Manila hemp or abaca stripping machine proposed herein, areorganization of the conventional processing methods would appearnecessary.

The tuxies or leaf sheaths 81, constituting the individual leaf stalksor trunks of the Manila hemp plant from which the tuxies or leaf sheaths81 are removed would have to first be classified and grouped togetheraccording to layer positions within the leaf stalks or trunks of theplant.

Two devices are most vital in the automated process embodied in ourstripping machine, namely, the gripping conveyors featured in almost allthe drawings from FIGS. 1 to 23 and the specially designed stationarystripper element sets illustrated in detail from FIGS. 24 to 29.

The gripping conveyors fundamentally and essentially would consist ofonly three sets, all of endless chain belt design, having difierentlengths which while operating in parallel, would have to overlap inorder to yield the contemplated results. Because of structurallimitations, however, what would have been the last set of conveyors isdivided into four sets in order to correspondingly divide the load uponthe single set of conveyors, as a result of the pull on all the tuxiesor leaf sheaths 81 being gripped by the set while performing thestripping process.

Each conveyor set basically consists of two chain belt conveyors eachequipped with bundles of cord or ropes rigidly fastened to the chainbelts in such a manner that the ropes of the upper conveyor will fitinto the spaces formed between the ropes of the lower conveyor.

As can easily be observed the lineal speeds of the two chain beltconveyors have to be identically the same so that any material tightlyplaced between them will be conveyed with a tightness of grip as aresult of the longitudinal meshing of the ropes throughout the conveyingoperation.

Two embodiments of the aforementioned tuxy or leaf sheath grippingconveying scheme are illustrated in FIGS. 18, 19 and 20.

At the outset, for purposes of economy and simplicity, rubber coveredropes 83 of uniform size, preferably with the fibers thoroughly rubberimpregnated are attached to each chain belt conveyor as mentioned above,in such a manner that the space between any two ropes 83 will be lessthan the diameters of the ropes. With the bottom conveyor of any one sethaving one more rope in number than the corresponding top conveyorplaced over it, the ropes 83 in the bottom of the top conveyor willpartially fit into the spaces and interstices between the ropes 83placed and held firm on the top of the lower conveyors to which they areattached. Consequently, any flat fibrous material placed between thechain belt conveyors such as Manila hemp or abaca tuxies or leaf sheaths81 or the stripped fibers resulting therefrom would be held tightly andpositively in corrugated form as shown in FIG. 18 so that the upper andlower sides of the sheaths are in direct contact with the adjoiningcomplementary surfaces of the upper and lower conveyors. The frictiondue to tightness of hold caused by the close fitting between the ropes83 would be sufficient to maintain the pull necessary for the squeezingaction between the blade and block in the process of stripping.

This gripping provision between the top or upper chain belt conveyorsand their corresponding lower counterparts thus described has causedsome design problems, however preliminary experiments and engineeringcalculations have shown that the two aforementioned conveying schemesare best suited for use in the present invention.

Referring to FIGS. 1, 2 and 4 and again to FIGS. 18, 19 and 20 as wellas to FIGS. 21, 22 and 23, it will be observed that both schemes arebased on the use of roller conveyor chains with bent attachment linkplates 86 interconnected by pins 89 upon which are mounted large rollers87 provided with grooves 88 which fit fixed rails built into rail plates90, fastly secured onto the framework around which the conveyors travel,by flat screws 91. The purpose of this arrangement is to prevent thechain belt conveyors from veering or swerving laterally or sidewisewhile the sets of conveyors draw the tuxies or leaf sheaths through theapparatus during the stripping process.

Because the lengths of sheaths 81 can vary anywhere from 1 meter andcentimeters (1.20 M) up to a maximum of 3 A meters (3.50 M) or 4 feet (4feet-0 inches) up to 12 feet (12 feet-O inches) it might be desirable toincorporate additional conveyors, preferably also of the chain beltguided type, but

intended for simple plain holding of leaf sheaths 81. Re-

gardless of the aforementioned conjectures arising from a carefulanalysis and study of FIGS. 18, I9 and 20 as well as of FIGS. 21, 22 and23. A clean wooden latticeor plain floor upon which the material can bedragged without getting soiled may be used instead of the additionalconveyors shown in FIGS. 18 through 23.

As already stated, FIGS. 18, 19 and 20 feature exclusively details ofthe first scheme as described. In the first embodiment, the roller chainconveyor links 86 appear fastened to plates 84 which hold the ropes 83by means of rivets 85. The pins 89 mentioned above, connecting linkplates 86 and holding large rollers 87 appear in the drawings with theheadless ends upset so as to be enlarged exactly as if they were rivets.At the outset however, the headless ends might be simply drilled inorder to admit cotter pins which in combination with plain cut washerswould lock the links 86 in'place. Typical leaf sheaths 81 are shownbeing pressed by ropes 83. In FIG. 18, four ropes 83 appear attached tothe top chain belt conveyor and five ropes are attached to the lowerchain belt conveyor in such a manner that the tuxies or leaf sheathsassume corrugations following the contours of the top and lower ropes 83in alternate positions. The ropes are fastened to holding plates 84 bymeans of small stranded wire strings 82. 1

The pressure between the top ropes 83 attached to the upper or top aswell as the bottom or lower chain belt conveyors with the tuxies or leafsheaths 81 in between them introduces a resistance to motion or gripwhich results in a pull on leaf sheaths 81, by the chain belt travelingconveyors. This pull on leaf sheaths 81 overcomes the resistance offeredby the squeezing action of the knife or blade and the opposing cushionblock of the stripping elements 65 and 74 encountered at appropriatespots in the travel of leaf sheaths 81 along the entire length of themachine, as shown in FIGS. 1, 2 and 3 and further detailed in FIGS. 18through 23. The leaf sheaths are thereby converted into the desiredvaluable fiber as well as the by-products rendered by the process.

A second embodiment would be the result of contemplated improvements onthe gripping device obtainable with the cooperation of rubber beltmanufacturers. With this end in view, an endless rubber belt 92 asdepicted in FIGS. 21, 22 and 23 can be positively fastened onto plates84A by means of rivets 85A each one of which would be fiat headed on oneend and headless on the other in preparation for proper conversion intoa button head after attachment. The rest of the parts of the chain beltconveyor which are common to both the first design as well as to thissecond embodiment bear exactly the same identification numbers in theFIGURES and the gripping effect upon the moving material is due to thesame fundamental principle used in the first embodiment. A distinctimprovement results from the corrugations of the rubber embedded ropesor cords within the belts, in that the leaf sheaths 81 are gripped moreeffectively.

Having described the design and construction of the conveyor sets,another innovation worth mentioning is the design and construction ofthe stripper element sets which are illustrated in FIGS. 1 and 2 andFIGS. 24 to 29 inclusive.

Two specially designed stripper element sets 65 and 74, one followingthe other, such as are depicted in detail in FIGS. 24,

25 and 26 as well as in FIGS. 27, 28 and 29, are secured by nuts 108tightened around foundation bolts 109 to the foundation base of themachine along the path of travel of leaf sheaths 81. The edges of theblades of the stripper element sets define boundary lines which separatethe stripping blocks of the sets from the edges of the correspondingblades upon which the blocks press with the leaf sheaths 81 to bestripped inserted inbetween.

The incorporation of the stripper element sets into the presentapparatus is as essential and vital to the operation of the strippingmachine as are the aforementioned gripping conveyors.

An understanding of the function of the stripper element sets isessential and necessary in order to understand the role played by themin order to secure automation of the process of stripping of the Manilahemp plant while producing expeditiously the highest grades of Manilahemp fiber possible through the use of the machine.

A distinctive feature of this invention is the method of insertion ofthe tuxies or leaf sheaths into the stripper element sets. These setsare shown in plan view in FIGS. 1 and 2 and side view in FIG. 3 whereinthe two automatic stripping outfits are seen to have elements which arecommon to both machines. The details would be best understood byreferring to FIGS. 24, 25 and 26, wherein the first stripper element setis met by the material to be stripped for the initial defibering on theshort, root-end portions or stubs of leaf sheaths 81. FIGS. 27, 28 and29 on the other hand would facilitate a better understanding of thefunction of the second stripper element set intended to complete theprocess of stripping by working upon the remaining unstripped portionsof the aforementioned leaf sheaths 81 which are carried along theconveyor path by the gripping conveyors.

As can be seen from the FIGURES leaf sheaths 81 are positively carriedby the conveyors on both sides of the stripper element sets and atdistinct periods of the processing are inserted into the wedge-shapedopening formed by the stripping blocks 70 and and the correspondingstripping blades or knives underneath them, namely 65 and 74respectively, the

stripping units in assembly constituting stripper sets 65 and 74appearing together with the conveyors in the profiles as shown in FIGS.3 and 5. The details of the individual stripping element units areportrayed in FIGS. 24 and 27, with cross-sections at certain points ofthe process shown in FIGS. 25 and 26 and in 'FIGS. 28 and 29. Thewedge-shaped ingresses or openings provided by the blade and block ofthe stripper element sets mentioned bear resemblance to the opened beaksof fowl.

Each of the stripper element sets have two ends or parts. The part orportion that first meets leaf sheath 81 which is the raw material to beprocessed, is the front or anterior end of the stripper element setunder consideration, set 65 being the first and set 74 the last to workon the leaf sheaths. The part or portion of the set that last contactsleaf sheath 81 during the stripping process is the rear or posterior endof the stripper element sets specified.

The front or anterior end identified as 69 in FIG. 24 in the case of thefirst stripper set and 79 in FIG. 27 in the case of the last stripperset is placed in such a position that the direction of its blade isparallel to the line of motion of the conveyors carrying the material.Thus the directions of the blades of the front or anterior end of thestripper element sets will always be installed parallel to the directionof travel of the material being processed, so that with the wedge-shapedopenings provided therewith, the stripper element sets will always bearranged to meet the material being carried by the conveyors.

A flattening of the edges of the knives or blades of the front portions69 and 79 of the stripping element units 65 and 74 shown respectively inFIGS. 25 and 28, with the corners of the flattened edges dulled or evenground round in order to preclude the cutting of any fibers or the pulpysections of leaf sheaths inserted into the stripper units is adistinctive feature of the present invention.

While in principle the two stripping element sets 65 and 74 (FIGS. 1 and2) are actually duplicates of each other, they will be found to beidentical with each other only in regard to symmetry. This means thatwith the forelegs of the stripping element sets 65 and 74 placed intheir respective positions, namely, in line with direction of travel andwith their respective wedge-like openings or ingresses 63 (FIGS. 24) and72 (FIG. 27) facing the material being conveyed, for example leafsheaths 81, the posterior leg 71 of the first element set 65 (FIGS. 1and 2) is directed to the left, while the posterior leg 78 of the secondand last element set 74 (FIGS. 1 and 2) is directed to the right.Moreover, these posterior legs 71 and 78 will also be found to greatlydiffer in length, the difference being caused by the lengths of thetuxies or leaf sheaths 81 that they will work on.

In the first stripper element 65 shown in FIG. 24, the insertion of leafsheaths 81 between the blade of set 65 and the corresponding wooden orplastic block 70 so that it gently presses upon the blade in preparationfor the actual stripping process is effected by conveyors 41 and 40shown in FIGS. 7 and 6 and conveyors 43 and 42 as shown in FIGS. 9 and8.

Similarly in the case of the last stripper element set 74 shown in FIG.27, insertion of the leaf sheaths between the blades of set 74 and thecorresponding wooden or plastic block 80 so that it gently presses uponthe blade in preparation to the actual stripping process is effected byconveyors 43 and 42 shown in FIGS. 8 and 9 and conveyors 45 and 44appearing in FIGS. 11 and respectively.

The rear or posterior ends of the stripper element sets start at points64 (FIG. 24) and 73 (FIG. 27) where the entire stripper element setsveer at an oblique angle of about 45 either to the left in the case ofstripper element 65 or to the right in the case of stripper element 74dependent upon the process requirements.

Right at these points where the veering occurs, i.e. points 64 and 73(FIG. 1), the round edges of the blades as shown in FIGS. 25 and 28,pertaining to the front or anterior portion, turn into the sharpfeatures of the hemp stripping knives exactly as in the case of handstripping. This is shown in FIGS. 26 and 29.

Considering the alternative design of the machine as shown by FIG. 2,which is almost identical to the embodiment shown in FIG. 1, thedifference being in the construction of the rear or posterior end of thestripper element sets as shown in FIG. 2. While the rear or posteriorends of the stripper element sets of the original machine shown in FIG.1 veer either to the left or right in straight lines to an angle of 45thereabouts, in the alternative arrangement of FIG. 2 the rear ends areformed in the shape of an arc or semicircle which turns to either theleft or to the right. Thus, if the rear or posterior ends have serratedblade edges instead of blunt blades, there will be no motionperpendicular to the line of pull upon the tuxies or leaf sheaths 81. Inthis manner, the darker and inferior grades of Manila hemp can beproduced in the same manner as the lighter and more expensive gradeswhich the original machine appearing in FIG. 1 is exclusively intendedto produce.

Referring to FIGS. 1, 2 and 4, wherein the conveyors are shown in planview, it will be observed that each successive leaf sheath belonging toany group previously classified according to the position or layer inthe trunk or leaf stalk of the plant is fed transversally into themachine or at right angles to the direction of travel, so that levelerplate 82 will place the butt ends of the tuxies or leaf sheaths in line,while they are carried by conveyors 41 and 43 along the respectiveentrance lengths or positions of the latter, as can be seen in the planview thereof appearing in FIGS 1 and 2. Because of the absence of topconveyors above them such as are shown in FIG. 4, and considering thestiffness of the material, the leaf sheaths are free to move at thestart sidewise or across the full width of the machine.

It is at this point that the additional simple or open type conveyors,previously mentioned, might be used in order to prevent dragging of theextremely long tuxies or leaf sheaths along the floor during thestripping process.

When the tuxies or leaf sheaths reach the midpoints of the lowerconveyors 41 and 43 shown in FIGS. 1 and 2, the top conveyors 40 and 42placed respectively over them as shown in FIG. 4, come into action bypressing down upon the tuxies or leaf sheaths of the lower conveyors,thereby holding the tuxies or leaf sheaths with a tight grip andassuring a positive pull thereupon.

With the tuxies or leaf sheaths thus held tightly by the two sets ofconveyors moving in parallel, assurance of their insertion into thewedge-shaped opening 63 shown in FIG. 24 because of the tapered or bevelcuts downwards upon the stripper blade 65 and upwards upon the stripperrectangular section shaped wooden or plastic pressure blocks 70 would beestablished.

The leaf sheaths continue travelling after their insertion into thestripper element set, identified in assembly as 65, until they reach theveering point 64 of the stripper element set.

Meanwhile, because of the fact that the edges of the stripper blade havepurposely been made round all over between points 63 and 64, which isthe foreleg portion of the stripper element set 65 instead ofmaintaining the conventional sharpness of comers common to the bluntstripping knives used in hand stripping, the slightest damage to thesliding tuxies or leaf sheaths during the insertion within the front oranterior portion of the stripper element set under consideration isaverted and forestalled.

Upon arrival of the tuxies or leaf sheaths at the veering point 64 shownin FIGS. 1 and 24, the following events occur in succession:

First, the travel of material carried by the chain belt conveyor setmade up of lower chain belt conveyor 41 and top chain belt conveyor 40ceases because the top and lower chain belt conveyors have reached theends of their travel upon coming to the turning points of theirrespective sprockets which cause their return to their starting points;Second, at the same time the chain belt conveyor set which consists oflower chain belt conveyor 43 and corresponding top chain belt conveyor42 continues to pull the tuxies or leaf sheaths because of the tighthold which it has on them; Third, as a result of the release from thefirst chain belt conveyor set made up of the lower chain belt conveyor41 and top chain belt conveyor 40 occuring during the first event, andwith the steady pull of the second chain belt conveyor set composed oflower chain belt conveyor 43 pressed upon by the top chain belt conveyor42 occuring during the second event, the leaf sheaths which havepreviously been inserted into the stripper set 65 up to the veeringpoint of the latter at point 64 or slightly past this point now turn tosuch a position as to be approximately at right angles with the veeredposterior length of stripper element set 65.

After the butt stubs at the root ends of the tuxies or leaf sheaths 81have been stripped by the pull of the second chain belt conveyor setcomposed of the lower chain belt conveyor 43 and the corresponding upperor top chain belt conveyor 42 the first of the series of the last orfinal chain belt conveyors becomes operative in the stripping process.It is made up of the lower chain belt conveyor 45 with the top or upperchain belt conveyor 44 installed over it. The set of chain beltconveyors thus described emerges in exactly the same row or line oftravel as the first set of chain conveyors mentioned made up of lowerchain belt conveyor 41 paired with top chain belt conveyor 40 over it.This set of chain belt conveyors which is composed of chain beltconveyors 45 and 44 gets hold of the defibered portion of the root endsof the partially stripped tuxies or leaf sheaths 81 at a spot adjoiningthe remaining unstripped lengths thereof and performs two functions:first, it contributes to the drawing effort solely exerted so far by thechain belt conveyors 45 and 44 for the stripping of what remains of theunstripped lengths of the root end portions of the tuxies or leafsheaths, and second, it causes the simultaneous insertion of the tuxiesor leaf sheaths into the wedge opening at point 72 of the foreleg 79.The bevel cuts on the stripping blade and corresponding stripping blocktogether make up a preliminary stripper element set 74 for the strippingof leaf end portions of the tuxies or leaf sheaths.

of the posterior leg or portion of the stripper'element to the rightwith respect to the direction of travel of the tuxies or leaf sheathstakes place.

The difference between FIGS. 1 and 2, is that in the machine shown inFIG. 1, the posterior leg of the stripper is in a straight line at anangle of 45 to the direction of travel, while in the machine depicted inFIG. 2, the same posterior leg is in the form of a curve which startstangent to the line of travel and follows a circular track or curve thatends just short of 180 from the starting tangent line.

Upon arrival of. the stripped butt end of the tuxies or leaf sheaths atthe veering point 73 of the stripper element set 74, (FIG. 27) thetravel of the conveyor set made up of lower chain belt conveyor 43 overwhich top chain belt conveyor 42 is placed, is cut short at points 14and (see FIGS. 1, 2 and 4) when, because of the turning of the chainsprockets involved, the chain belt conveyors are made to return back totheir starting points. Meanwhile, the chain belt conveyor set which ismade up of the lower chain belt conveyor 45 and top chain belt conveyor44 over it, continue its travel carrying with it with a firm gripthe-partially stripped tuxies or leaf sheaths 81, thereby pulling theunstripped portions past the posterior leg. 78 of the stripper element74 made of stripping block 80 pressing -upon stripping blade 74 as whownin FIG. 27 of .thedrawings, beyond the veering point 73 which isadequately prepared to strip the remaining portions of the tuxies orleaf sheaths fed into the machine. Considering FIGS. 1 and 2 it appearsthat the action by the chain belt conveyors 45 and 44 and all theconveyors preceding and following, consists simply in an uninterruptedforward travel such that the material is carried all the way throughwith a firm hold. However, within the uninterrupted and unidirectionaltravel mentioned, there actually occurs a reversal of stripping actionon the unstripped portion of the leaf sheaths with respect to thestripper elements initially through stripper element set 65 and finallythrough stripper element 74.

The reversal of the stripping action is mainly caused by the relativepositions of the conveyors as they pull the leaf sheaths through thestripper elements. Furthermore the swerving of the posterior ends of thestripper element sets to either the left or to the right, makes itpossible to strip the tuxies or'leaf sheaths'by pulling them to theright or to the left past the corresponding stripping element unitconcerned so as to thereby obtain exactly the same action effected ofhand or spindle machine stripping i.e., first in one direction and thenin the reverse direction. Since the tuxies are in the posterior leg 78of the stripper element set 74, where the blade has exactly the samesection features of a stripping knife such as is used in hand stripping,the remaining unstripped lengths of the tuxies must be stripped whilebeing pulled towards the left past the final stripper element set 74,with sufficiently large towing force behind the grip pull conveyor setsmade up of successively lower conveyors 45, 47, 49 and 51 with topconveyor counterparts 44, 46, 48 and 50, to take care of all leafsheaths simultaneously being stripped. This is shown in FIGS. 1, 2 and4, with side elevations appearing in FIGS. 3 and 5, details of theconveyors being portrayed in FIGS. 6, 7, 8 and 9, l0 and 11, 12 and l3,l4 and 15 and 16 and 17 not to mention the detail illustrationsdepicting stripper element sets portrayed in FIGS. 24, 25 and 26 as wellas in FIGS. 27, 28 and 29.

The stripping process as described above is exactly the same as that ofhand stripping Manila hemp or abaca, particularly in the initial stageswhen the process is performed upon the root end butts or portions of theleaf sheaths. The difference between this novel method and the oldconventional system is that the present invention is capable of handlinga much greater number of leaf sheaths. Relying upon the abundance ofpower available for driving the present invention and its automaticelements, particularly in the case of the arrangement detailed in FIG. Iwhich is designed for the production of the highest quality Manilafiber, it is estimated that no less than a hundred fold advantage wouldbe obtainable by the use of the present invention as contrasted toexisting methods of stripping fibers.

The sap secreted by the leaf sheaths of the plant reacts with the plainhigh carbon steel cut of which the stripping blades are made. Underpresent practice the sap squeezed out of the leaf sheaths turns into aviscous black liquid which can contaminate and stain the resultingfibers, thereby decreasing their commercial grade.

For this reason, and because of the possibility of utilization of theby-products recoverable from stripping, it is better to replace theconventional high carbon, or tool steel blades with either stainlesssteel blades or a non-ferrous alloy blade which is capable of beinghardened and tempered or with blades made out of some other materialsuch as porcelain or glass which do not possess the property of reactingwith the sap of the abaca plant.

It is to be understood that each of the above-described ele ments, ortwo or more together, may also find a useful application in other typesof stripping machines which differ from the type described above.

While the invention has been illustrated and described as embodied inthis stripping machine it is not intended to be limited to the detailsshown, since various modifications and structural changes may be madewithout departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpointof prior act, fairly constitute essentialcharacteristics of the generic or specific aspects of this invention.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims:

1. Apparatus for defibering sheaths of fibrous material, particularlysheaths of abaca, comprising a plurality of elongated conveyor meanseach comprising an upper and a lower endless conveyor having adjacentruns for positively engaging opposite surface portions of sheathstherebetween for transporting successive sheaths sideways along apredetermined path, said plurality of conveyor means comprising at leasttwo conveyor means aligned in longitudinal direction and spaced fromeach other in that direction so as to provide a gap between the trailingend of one of said two conveyor means and the leading end of the otherof said two conveyor means, and a third conveyor means extendingsubstantially parallel to said two conveyor means laterally spacedtherefrom and having a leading end upstream of said gap and a trailingend downstream of said gap but upstream of the trailing end of saidother conveyor means; and a pair of stripping means each comprising astationary stripping blade having an edge and extending with at leastone portion thereof transverse to the direction of said path andpressing means for pressing said sheaths during the travel thereof alongsaid path against said edge so as to strip pulpy material from thefibrous material of the sheath, the edge portion of one of saidstripping means being located in said gap and the edge portion of theother stripping means being located closely adjacent and downstream ofthe trailing end of said third conveyor means.

2. An apparatus as defined in claim 1, wherein each of said upper andlower conveyors includes a plurality of bundles of flexible cordsarranged parallel to said path of travel, and imparting to said surfacesan undulate contour, the surfaces of said upper conveyor beingcomplementary to the surfaces of said lower conveyor.

3. Apparatus as defined in claim 1, and including drive means connectedto said plurality of conveyor means for simultaneously moving said runsof said upper and lower endless conveyors in longitudinal direction ofsaid path.

4. Apparatus as defined in claim 1, wherein each of said strippingblades has a leading portion extending substantially in the direction ofsaid path, whereas said portion extending transverse to the direction ofsaid path forms a trailing portion of each blade.

5. Apparatus as defined in claim 4, wherein the trailing portion of theblade of one of said stripping means extends to one side of its leadingportion, whereas the trailing portion of the blade of the other of saidstripping means extends to the other side of its leading portion.

6. An apparatus as defined in claim 4, wherein each of said trailingportions includes an obtuse angle with the respective leading portion.

7. An apparatus as defined in claim 4, wherein said trailing portion iscurved in a direction transverse to said leading portion.

8. An apparatus as defined in claim 4, wherein said pressing meanscomprise a block for each of said stripping blades arranged for pressingthe sheaths against said edges of said blades.

9. An apparatus as defined in claim 8, wherein the leading portion ofeach blade has a front edge curved rearwardly and upwardly toward therespective block and wherein each of said blocks has a front face curvedrearwardly and downwardly towards the edge of the respective blades.

1. Apparatus for defibering sheaths of fibrous material, particularlysheaths of abaca, comprising a plurality of elongated conveyor meanseach comprising an upper and a lower endless conveyor having adjacentruns for positively engaging opposite surface portions of sheathstherebetween for transporting successive sheaths sideways along apredetermined path, said plurality of conveyor means comprising at leasttwo conveyor means aligned in longitudinal direction and spaced fromeach other in that direction so as to provide a gap between the trailingend of one of said two conveyor means and the leading end of the otherof said two conveyor means, and a third conveyor means extendingsubstantially parallel to said two conveyor means laterally spacedtherefrom and having a leading end upstream of said gap and a trailingend downstream of said gap but upstream of the trailing end of saidother conveyor means; and a pair of stripping means each comprising astationary stripping blade having an edge and extending with at leastone portion thereof transverse to the direction of said path andpressing means for pressing said sheaths during the travel thereof alongsaid path against said edge so as to strip pulpy material from thefibrous material of the sheath, the edge portion of one of saidstripping means being located in said gap and the edge portion of theother stripping means being located closely adjacent and downstream ofthe trailing end of said third conveyor means.
 2. An apparatus asdefined in claim 1, wherein each of said upper and lower conveyorsincludes a plurality of bundles of flexible cords arranged parallel tosaid path of travel, and imparting to said surfaces an undulate contour,the surfaces of said upper conveyor being complementary to the surfacesof said lower conveyor.
 3. Apparatus as defined in claim 1, andincluding drive means connected to said plurality of conveyor means forsimultaneously moving said runs of said upper and lower endlessconveyors in longitudinal direction of said path.
 4. Apparatus asdefined in claim 1, wherein each of said stripping blades has a leadingportion extending substantially in the direction of said path, whereassaid portion extending transverse to the direction of said path forms atrailing portion of each blade.
 5. Apparatus as defined in claim 4,wherein the trailing portion of the blade of one of said stripping meansextends to one side of its leading portion, whereas the trailing portionof the blade of the other of said stripping means extends to the otherside of its leading portion.
 6. An apparatus as defined in claim 4,wherein each of said trailing portions includes an obtuse angle with therespective leading portion.
 7. An apparatus as defined in claim 4,wherein said trailing portion is curved in a direction transverse tosaid leading portion.
 8. An apparatus as defined in claim 4, whereinsaid pressing means comprise a block for each of said stripping bladesarranged for pressing the sheaths against said edges of said blades. 9.An apparatus as defined in claim 8, wherein the leading portion of eachblade has a front edge curved rearwardly and upwardly toward therespective block and wherein each of said blocks has a front face curvedrearwardly and downwardly towards the edge of the respective blades.